Soluble pilymers having essentially the structure of polyalkenamer chloro-nitroesters and methods of preparing same

ABSTRACT

IN SOLUTION IN AN ORGANIC SOLVENT, WITH TERT. BUTYL HYPOCHLORITE AND WITH AQUEOUS NITRIC ACID IN A CONCENTRATION NOT HIGHER THAN 85%.   in which R and R&#39;&#39; are Cl or -O-NO2, R and R&#39;&#39; being different. A method for preparing the new polyalkenamer chloro-nitroesters is also disclosed and comprises reacting a polymer the macromolecules of which consist essentially of one or more repeating units -CH CH - (CH2-)n and/or   in which n is a whole number from 2 to 10, and/or formula II:   New soluble substituted polyakenamers are disclosed, the macromolecules of which consist, predominantly or essentially, of one or more repeating units which are the same or different and which have formula I:

United States at'ent DallAsta et al.

[11] 3,821,183 June 28, I974 SOLUBLE POLYMERS HAVING ESSENTIALLY THESTRUCE 0F POLYALKENAMER CHLORO-NITROESTERS AND NETHODS OF PREPARING SAME[75] Inventors: Gino DallAsta; Pietro Meneghini;

Ugo Gennaro, all of Milan, Italy [73] Assignee: Montecatini Edison S. p.A., Milan,

Italy 22 Filed: 0ct.25, 1972 [21] Appl. No.: 300,861

[30] Foreign Application Priority Data Oct. 26, 197i Italy 303l4/7l [52]US. Cl 260/93.l, 260/32.4, 260/32.8 N,

260/33.6 UA, 260/338 UA, 260/80.78, 260/82.l, 260/85.l, 260/88.2 F,260/94.7 N,

Primary Exqminer-Stanford M. Levin I [57] ABSTRACT New solublesubstituted polyakenamers are disclosed,

the macromolecules of which consist, predominantly or essentially, ofone or more repeating units which are the same or different and whichhave formula I:

in which n is a whole number from 2 to 10, and/or formula II:

in which R and R are Cl or ONO R and R being different.

A method for preparing the new polyalkenamer chloro-nitroesters is alsodisclosed and comprises reacting a polymer the macromolecules of whichconsist essentially of one or more repeating units CH =CH (CH and/or insolution in an organic solvent, with tert. butyl hypochlorite and withaqueous nitric acid in a concentration not higher than 85%.

12 Claims, No Drawings l SOLUBLE POLYMERS HAVING ESSENTIALLY THESTRUCTURE OF POLYALKENAMER CHLORO-NITROESTERS AND METHODS OF PREPARINGSAME Soluble polymers consisting essentially of units containing achlorine group and an organic ester group bound to two adjacent carbonatoms were described in our US application Ser. No. 189,341, filed Oct.14, 1971, US. Pat. No. 3,772,260, and in our Italian Pat. No. 918,366.

Said United States application and Italian patent disclosed polymerscontaining ester groups derived from monobasic organic acids containingfrom 1 to 18 carbon atoms, which organic ester groups impart specialproperties to the polymers as, for instance, solubility in certainsolvents, glass transition temperatures within a given temperaturerange, or particular mechanical properties.

To the best of our knowledge no polyalkenamers the macromolecules ofwhich contain nitroester group in predominantly or essentially all ofthe repeating units were known in the art prior to our presentinvention.

The solubility of our polyalkenamer chloronitroesters in commonlyavailable solvents is surprising and unexpected when it is consideredthat related polymers the ester groups of which consist of residues ofsulfuric or phosphoric acid are not linear and soluble but, on thecontrary, are cross-linked and insoluble. Our new polymers are stableand this is also surprising and unexpected considering that the nitricacid used in preparing them usually exerts an oxidizing and destructiveaction on polymers used as starting material either during treatment ofthe polymer with the acid, or subsequently.

The presence of the nitroester groups in our substituted polyalkenamersimparts properties to the products which clearly distinguish them fromprior substituted polyalkenamers as referred to hereinabove. Thedistinguishing characteristics include excellent resistance to chemicalagents, both acid and basic; good adhesion to metal surfaces; very goodtransparency, and a high degree of solubility in several commonsolvents. By virtue of such properties the present products are usefulas film-builders in paints and in particular in acid-resisting paints.

The products of this invention, and in particular those having averyhigh molecular weight corresponding to an intrinsic viscosity intoluene at 30C of not lower than 1.5 dl/g, have, also, high values fortheir mechanical properties, particularly their tensile yield strength.Furthermore, these products are easily hotmolded in a press or bycalendering to transparent, non-brittle films or plates having excellentmechanical resistance. Additional characteristics of products within thescope of this invention are easy inflammability and quick combustionwhich favor use thereof as slow-combustion explosives or as fuses.

The products of this invention may have varying molecular weightscorresponding to intrinsic viscosities in toluene at 30C of from about0.5 dl/g to 1.5 dl/g and m higher. Those of lower molecular weightcorresponding to an intrinsic viscosity in toluene at 30C of about 0.lto 0.5 dl/g are generally oily, waxy or semi-solid materials, which canbe easily used to fill molds or hollows and are, therefore, plasticexplosives.

While the invention provides chloronitropolyalkamers the macromoleculesof which consist predominantly or essentially of units having for mula Iand/or formula II, and wherein n in formula I is a whole number, thepresently preferred chloronitropolyalkamers are those in which in theunits of formula I n is a whole number from 2 to 10. Thechloronitropolyalkamers which are presently preferred are those inwhich, in the units of formula I present therein, n equals 2, 3, 6 or10. In such a given chloronitropolyalkamer of the invention, n may be 2,3, 6 or 10 in all units having formula I, or the units of formula I mayhave varying lengths along the macromolecular main chain, in which casen will vary and can be 2 in some units of formula I, and have adifferent value of 3, 6 and/or 10 in other units of formula I. That isto say, in all units of formula I present in the linear macromolecularmain chain It may equal a given whole number such as2, 3, 6 or 10, or inone or more units of formula I n may equal 2, for instance, and have adifferent value, e.g., 3, 6 or 10 in other units of formula I.

Solvents which are particularly suitable for preparing highlyconcentrated solutions of the polymers of this invention includemethylene chloride, nitrobenzene, acrylonitrile, acetonitrile,nitromethane, methyl nhexylketone, tetrahydrofuran, acetone, dioxane,dimethylformamide and cyclohexanone.

The polymers of this invention the macromolecules of which consistpredominantly of units having formula I and/or formula II may alsocontain minor amounts of units corresponding to other formulae, whichmay be due either to incompleteness of the reaction by which the unitsof formual l or of formula II are formed, or to secondary reactions. Ingeneral, the extraneous units which may be present in the polymers arethose having the formulae III, IV, V, VI and VII as shown below:

, eese.

When units having formulae Ill and/or IV are present, the olefinicunsaturations thereof can be utilized to vulcanize the polymers or tointroduce other groups such as, for example, those described in our US.application Ser. No. 189,341 and in our Italian patent No. 91 8,366referred to hereinabove.

Various properties of two typical high molecular weight polymersaccording to this invention are shown in the following table:

' Properties Measurement unit C1 N 2 C1 0 N O Chlorine content Percentby weight 5 8 Iodine number 5 5 Intrinsic viscosity in cycloliexanone at30 C D1, 1 5 7 Glass transition temperature C. 56 31 Density at 30 CGu't. 44 1 38 Water absorption (standard ASTM D 570 63). Percent. 0 b 1Transparency (standard ASTM D 1003 61 Percent. 91. 5 1 Diffusion(standard ASTM D 1003/61 13 Transparency at -1.500 A g 5 Flexnralmodulus on lamina. 41'000 V Tensile yield strength... 630 Combustionrate Q 25 0' ow (weight loss: 10 160 155 Limit. of thermal stability iIt was not only surprising that the stable, soluble 5 cess for producingthe chloro-nitropolyalkamers of the polymers of this invention canexist. it was also surprising and unexpected that they could be obtainedby treating polymers made up essentially of one or more repeating unitsof formula 11, 1V or V11 as shown above, in solution in an organicsolvent, with nitric acid and tert. butyl hypochlorite, withoutoxidizing and destructive effects on the starting polymer by thenitricacid.

drous nitric acid, for preventing the formation of an emulsion duringmixing of the organic solvent in which the starting polymer isdissolved, such as the preferred methylene chloride, undesired sidereactions occur such as, for instance, oxidation of the polymeric chainof the starting polymer and its consequent degradation to tarry productsof indefinite nature.

By operating with aqueous nitric acid in which the acid concentration isnot higher than 85%, for instance at a nitric acid concentration of 65%by weight, the desired reaction, i.e., the formation of thepolyalkamerchloronitroesters takes place practically exclusively. Suchresult is surprising and particularly so when it is considered that theformation of the esters does .not take place in a purely organic phasebut in an emulsion of methylene chloride and the water of the aqueousnitric acid used and that, in consequence, both the starting polymer andthe tert. butyl hypochloride are contained in the organic phase whilethe nitric acid is essentially present in the aqueous phase.

In spite of the existence of the two different phases, we have foundthat the reaction can be conducted until practically all of the doublebonds of the starting polymer are saturated by operating at temperaturesof from 50C to +50C, preferably from -30C to +35C, for reaction timesvarying, according to the temperature, from 2 to 24 hours, preferablyfrom 2 to 10 hours, with an amount of tert. butyl hypochlorite comprisedbetween 10 and 1.5 moles, preferably between 1.0 and 1.3 moles per moleof starting homopolymer double bonds, and with an amount of nitric acidbetween 1.0 and 1.5 moles, preferably between 1.0 and 1.25 moles, permole of starting homopolymer double bonds.

Use of a particular catalyst is not required in our proinvention.

in general, a solution of the starting polymer in methylene chloride orother solvent containing the polymer in a concentration of from 0.2% to20% by weight, preferably of from 0.1% to 10% by weight are used. Higherconcentrations may be used if the starting polymer 1S oily and has acomparatively low molecular weight corresponding to an intrinsicviscosity in toluene at 30C of from about 0.1 to 0.5 dl/g.

Since the chloro-nitroesterification reaction is highly exothermic, itis necessary to subject the reaction mixture to intense cooling,especially when a high concentration of the starting polymer is used.

The reaction mixture is stirred vigorously, or circulated rapidly, toaccelerate and control the chloro-nitroesterification reaction.

A schematic showing of the continuous reaction process is shown below:

recovery solvent polyalkamer chloro-nitroester unsaturatedpolyhydrocarbon purified solvent preparation of tert. butyl 4hypochlorite (2) recovered I r '(OHsh NaOH As is apparent from theschematic showing, butyl alcohol s essentially regenerated from thereacted tert. butyl hypochlorite and recycled for use in preparing:rddmonal tert. butyl hypochlorite for use in the reacion.

The solvent is also essentially recycled, the materials consumed beingthe starting homopolymer, nitric acid, caustic soda and chlorine. Theproducts of the reaction are the chloro-nitroesterified startinghomopolymer and sodium chloride.

The starting polymers used are those the monomeric units of whichcorrespond to formulae Ill, and/or 1V, or V11 as shown above. Of thepolymers the units of which correspond to formula 111, the preferredones are those in which n is 2, 3, 6 or 10 and is the same or differenti ples of such polymers are polybutadiene in which the units derivedfrom butadiene have prevailingly 1,4-cis or 1,4-trans structure, or inwhich some of the units derived from the monomer have 1,4 cis structureand others show 1,4 trans enchainment; the polypentenamer, thepolyoctenamer and the polydodecenamer having double bonds which areprevailingly cis, prevailingly trans, or a mixture of the two types; andbutadienestyrene copolymers. Said starting polymers may be of eitherhigh or low molecular weight.

While it is possible to saturate all of the double bonds of the startingpolymer, it is also within the purview of this invention to use thenitric acid and tert. butyl hypochlorite in amounts insufficient tosaturate all of the double bonds of the starting polymer and thus obtainend products containing a certain amount of double bonds in addition tounits of formula l or 11.

The polyalkamer chloro-nitroesters prepared under the conditionsspecified herein always have an intrinsic viscosity such as to provethat the starting polymer has not undergone any molecular weightdegradation or only very limited molecular weight degradation, duringthe chloro-nitroesterification. t

The polyalkamer chloro-nitroesters are generally separated from thereaction mixture, after the chloro-nitroesterification by coagulationwith precipitants such as methanol and appear white or yellowishpowders.

The following examples are given to illustrate the present industrialinvention, and are not intended to be limiting.

EXAMPLE 1 30 g of commerical 1,4 cis-polybutadiene containing 92.4% ofdouble cis-bonds, 4% of double trans-bonds, 3.6% of butadiene units, andhaving an intrinsic viscosity in cyclohexanone at 30C of 2.20 dl/g, aredissolved in 3 l of methylene chloride. 50 ml of 65% nitric acid areadmixed thereto under stirring and at room temperature. By means of adropping-funnel 75 ml of tert. butyl hypochlorite are added overminutes.

During the reaction the temperature rises to 35C.

The whole is reacted for 4 hours under stirring and the reaction productis coagulated in methanol.

76 g of a pulverulent white polymer are obtained, having characteristicsas follows:

intrinsic viscosity in cyclohexanone at 30C 2.50 dl/g glass transitiontemperature 56C density at 3()C 1.44 g/cm" iodine number 0] The polymeris soluble in chlorinated solvents and in polar solvents such as acetoneor acetonitrile. There are no unsaturations. The chlorine content 25.5%.

EXAMPLE 2 6.0 g of polymer in the form of a white powder are thusobtained. It is soluble in chlorinated solvents (for instance methylenechloride) and polar solvents (for example acetone) and exhibits thefollowing characteristics;

chlorine content 253% iodine number O.5 intrinsic viscosity 2.13dl/gmeasured in cyclohexanone at 30C.

EXAMPLE 3 20 g of trans-polypentenamer (containing 20% of doublecis-bonds and of double trans-bonds and having a viscosity in toluene at30C of 1.89 dl/g) are dissolved in 2 liters of methylene chloride. Atroom temperature and under stirring, 30 ml of 65% nitric acid and, bymeans of a droping-funnel, 45 ml of tert. butyl hypochlorite are admixedover 15 minutes. The whole is allowed to react for 4 hours understirring: it

is then coagulated in methanol.

43 g of pulverulent white polymer having the following characteristicsare thus obtained:

30g of polydodecenamer containing of double trans-bonds and 15% ofdouble cis-bonds, and having an intrinsic viscosity in cylohexanone at30C of 1.8 dl/g, are dissolved in 2 liters of methylene chloride. Understirring and at room temperature, 20 m1 of 65% nitric acid are added.Subsequently, 25 ml of tert. butyl hypochlorite are dripped from adropping-funnel in 10 minutes. During the reaction the temperature risesto 35C. After 6 hours and under intense stirring the polymer is isolatedby coagulation in methanol. 44 g of a pulverulent white polymer havingthe following characteristics are thus obtained:

1.95 dl/g intrinsic viscosity in cyclohexanone at 30C glass transitiontemperature The polymer is soluble in solvents such as methylenechloride and acetonitrile.

EXAMPLE 5 After a dipping period of 48 hours, the laminas are washedwith water. All four laminas exhibit deep corrosions in the non-coatedparts, while the parts coated with the polymer film are still perfectlyspecular. The films are removed from the laminas after the treatment.All of them are still thoroughly soluble in the abovementioned solventssuch as the solvents of the polymers of this invention.

As will be apparent, changes and variations in details can be made inpracticing this invention, without departing from its spirit. Therefore,we intend to include in the scope of the appended claims all suchmodifications as will be obvious to those skilled in the art from thedescription and working examples given herein.

We claim:

1. Solid substituted polyalkenamers the macromolecules of which consistessentially of one or more repeating units having the following formula:

and/or the following formula:

CH2CH lee-1. HQ JR wherein R and R are Cl or O-NO R being alwaysdifferent from R and, optionally, up to of units represented by aformula selected from the following formulae wherein n is a whole numberfrom 2 to 10;

CH CH (CH CHa-CH- CHCl CHCl (CH and CHr-CH HC1CHzC1;or;

optionally, up to 25% of units derived from monomeric styrene.

2. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula CH-CH-(CHr-h,

1 NO; in

wherein n is a whole number from 2 to 10.

3. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula CH-CH-(CHg-h,

wherein n 2.

4. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula wherein n 3.

5. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula wherein n 6.

6. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula wherein n 10.

7. Process for preparing high molecular weight, substitutedpolyalkenamers consisting essentially of one or -more repeating unitshaving the formula wherein R and R are C1 or -O-NO R being alwaysdifferent from R, characterized in that a homopolymer the macromoleculesof which consist essentially of one or more repeating units wherein n isa whole number from 2 to 10 CH CH (CH and/or is reacted, at atemperature comprised between 50C and +50C, in an organic solventsolution, with tert.butyl hypochlorite in an amount comprised between1.0 and 1.5 moles, per mole of double bonds in the starting polymer, andwith aqueous nitric acid at a nitric acid concentration not higher than8.'Process according to claim 7, characterized in that the reaction iscarried out at temperatures comprised between 30C and +35C.

9. Process according to claim 7, characterized in that the reaction iscarried out with an amount of tert. butyl hypochlorite in an amountcomprised between 1.0 and 1.3 moles, per mole of double bonds in thestarting polymer.

10. Process according to any of claim 7, characterized in that it isoperated with nitric acid amounts ranging from 1 to 15 moles, per moleof double bonds of the starting polymer.

11. Process according to any of claim 7, characterized in that it isoperated with nitric acid amounts ranging from 1 to 1.25 moles, per moleof double bonds of the starting polymer.

l2. Substituted polyalkenamers according to claim 1,

in the form of film-building products for paints having

2. Polyalkenamers according to claim 1, characterized in that themacromolecules thereof consist essentially of repeating units havingformula
 3. Polyalkenamers according to claim 1, characterized in thatthe macromolecules thereof consist essentially of rePeating units havingformula
 4. Polyalkenamers according to claim 1, characterized in thatthe macromolecules thereof consist essentially of repeating units havingformula
 5. Polyalkenamers according to claim 1, characterized in thatthe macromolecules thereof consist essentially of repeating units havingformula
 6. Polyalkenamers according to claim 1, characterized in thatthe macromolecules thereof consist essentially of repeating units havingformula
 7. Process for preparing high molecular weight, substitutedpolyalkenamers consisting essentially of one or more repeating unitshaving the formula
 8. Process according to claim 7, characterized inthat the reaction is carried out at temperatures comprised between -30*Cand +35*C.
 9. Process according to claim 7, characterized in that thereaction is carried out with an amount of tert. butyl hypochlorite in anamount comprised between 1.0 and 1.3 moles, per mole of double bonds inthe starting polymer.
 10. Process according to any of claim 7,characterized in that it is operated with nitric acid amounts rangingfrom 1 to 1.5 moles, per mole of double bonds of the starting polymer.11. Process according to any of claim 7, characterized in that it isoperated with nitric acid amounts ranging from 1 to 1.25 moles, per moleof double bonds of the starting polymer.
 12. Substituted polyalkenamersaccording to claim 1, in the form of film-building products for paintshaving excellent adhesiveness and resistance to chemical agents.